Sizing Fortinet 300C To ASA Series

We are currently in a position to be needing an ASA series firewall. We currently have dual redundant Fortinet 300C's in place. The reason we are wanting the ASA series is the way we are designing our VOIP system is we will be utilizing the 9900 series cisco phones with the any connect VPN. We are also going to structure our BYOD deployment around the any connect VPN.

My first step is to find an ASA firewall that is comparable to the 300C's that we have now.

We have 350 "internal" clients on an MPLS network at 20 remote sites. All of the internet to these sites comes back to our HQ where the firewalls are located. The MPLS is 30Mbps to the internal and 15Mbps to the internet. The fortinets do web content filtering, traffic logging, DMZ separation, NAT, and we will replace our Juniper SA2000 VPN with the ASA firewall as well. We are looking at roughly 125 VPN clients.